Approximately one in five patients with elevated office blood pressure (BP) has normal BP when measured out of the office using ambulatory BP monitoring (ABPM). This condition, known as white-coat hypertension, confers minimal increased cardiovascular risk and does not require antihypertensive treatment. Failure to detect white-coat hypertension places patients at risk for adverse effects from BP medications and unnecessarily increases healthcare costs. Accordingly, the U.S. Preventive Services Task Force (USPSTF) recently published a draft update of their hypertension screening guideline in which they recommended that patients with elevated office BP undergo ABPM prior to being diagnosed with and treated for hypertension. Despite the strong, consistent evidence in support of this guideline, ABPM is infrequently used in the U.S. The goal of this proposal is to develop and test an intervention that will increase uptake of the USPSTF hypertension screening guidelines in diverse primary care settings. We will first conduct pre-implementation focus groups with primary care patients and providers from a large ambulatory care network that serves a vulnerable patient population to increase the understanding of the barriers and facilitators to implementing this USPSTF guideline. We will next refine an implementation strategy comprised of 1) educational activities that increase knowledge of the guidelines; 2) a computerized clinical decision support tool that facilitates ordering of ABPM when indicated by the guideline; and 3) a culturally-adapted, easily accessible ABPM service. We will then conduct a 2-year cluster randomized clinical trial in which we randomize 8 primary care clinics in the network to either 1) the multifaceted guideline implementation intervention or 2) a wait-list control group. At the end of the trial, we will assess the effectiveness of the intervention at increasing the proportion of indicated patients who complete ABPM. We will also conduct post-implementation focus groups of patients and providers to assess whether the intervention can be sustained within the ambulatory care network and should be disseminated to other practice settings.